| 摘要 |
<p>The particulate filter (40) comprises a monolithic material (44) for filtering soot particles from the exhaust gas, a first coating (52) of the monolithic material, a second coating of the monolithic material, a third coating (56) of the monolithic material, an upstream portion of exhaust gas inlet, a downstream portion (20) for discharging the exhaust gas, and an upstream portion for admission of the exhaust gas. The first coating comprises an oxidation catalyst, and the second coating comprises a catalyst for selective catalytic reduction. The particulate filter (40) comprises a monolithic material (44) for filtering soot particles from the exhaust gas, a first coating (52) of the monolithic material, a second coating of the monolithic material, a third coating (56) of the monolithic material, an upstream portion of exhaust gas inlet, a downstream portion (20) for discharging the exhaust gas, and an upstream portion for admission of the exhaust gas. The first coating comprises an oxidation catalyst, the second coating comprises a catalyst for selective catalytic reduction, and the third coating comprises a combustion catalyst of soot particles. The three coatings are distributed so that the exhaust gas first meet the third coating, then the second coating and finally the first coating. The second coating is impregnated in the thickness of the monolithic material. The first coating and/or the third coating are uniformly or non-homogenously impregnated on an external surface of the monolithic material. The third coating is mainly impregnated on an outer surface of the monolithic material present on the side of the upstream part of the particulate filter. The first coating is mainly impregnated on the outer surface of the monolithic material present on the side of the downstream portion of the particulate filter. The second and third coatings have same formulation and chemical composition. The catalyst of the third coating comprises less precious metal than the catalyst of the first coating.</p> |
